Natural Language Processing · TEE · papers
Q2A · Morpheme, lexeme and NER
Solved final paper · December 2025
Actual final examination · 2 December 2025 · 100 marks · 3 hours
ii. Discuss the significance of NER in three different NLP applications. [10 marks]
Answer
i. Morpheme and lexeme
A morpheme is the smallest linguistic unit that contributes meaning or grammatical function. A lexeme is an abstract vocabulary item representing a family of inflected word forms.
| Basis | Morpheme | Lexeme |
|---|---|---|
| Unit | A meaningful component of a word | An abstract dictionary vocabulary item |
| Examples | un-, happy, -ness; cat and plural -s | RUN covers run, runs, ran and running |
| Independence | Free morphemes can stand alone; bound morphemes cannot | A lexeme is realised through one or more word forms |
| NLP relevance | Morphological segmentation, stemming and analysis | Lemmatization and lexical meaning |
“Cats” contains two morphemes: cat + plural -s. “cat” and “cats” are forms of the lexeme CAT. “Unhappiness” can be segmented into un + happy + ness, although its spelling changes at the boundary. A morpheme and a syllable are different: syllables concern pronunciation, while morphemes concern meaning or grammar.
ii. Named Entity Recognition in applications
NER locates spans that name entities and assigns types such as PERSON, ORGANIZATION, LOCATION, DATE or domain-specific categories.
| Application | Entities and example | Why NER matters |
|---|---|---|
| News information extraction | “Asha joined Infosys in Pune.” → Asha/PERSON, Infosys/ORG, Pune/LOCATION | Creates searchable people–organisation–location records and supports later relation extraction |
| Healthcare document processing | Find disease, drug and dosage spans in a clinical note | Supports record indexing and medication extraction; specialist labels and validation are required |
| Customer support and commerce | Extract product names, dates and order identifiers from “My Pixel arrived damaged on Monday.” | Routes complaints, links the correct product and fills structured support fields |
NER answers “Which entity spans occur here, and what type are they?” It does not by itself establish every relation between those entities or resolve all names to unique real-world identities.
Yaad rakho: Morpheme = word ka meaningful piece; lexeme = word family. NER = naam dhoondho aur type do.